Making a surprise appearance alongside Who star Jenna Coleman at the London Film and Comic Con, the 51-year-old also expressed his gratitude for those fans who have avoided reading the five scripts.

Earlier this week BBC Worldwide - the Beeb’s commercial arm - apologised to the programme's fans and promised to investigate the "security issue" after the documents were accessible to all on the internet.

It is believed the blunder occurred in BBC offices recently opened in Miami.

Showrunner Moffat, who confirmed he has started writing this year’s Christmas special, also told fans at the cult entertainment expo that former Time Lord star Matt Smith’s final filmed – but not broadcast - scene featured him in a harness with his trousers down.

The Glasgow-born writer, who last year admitting to ‘lying his a*** off for months’ ahead of Who’s 50th anniversary celebration episode, also said he has a snap of Sherlock stars Benedict Cumberbatch and Martin Freeman in costume in the TARDIS.

But he ruled out a crossover between the two hit shows, saying: "It can't happen".

He also revealed some "nasty" and "unpleasant" scenes were coming up for the eight series, scheduled to begin on August 23.

New Doctor Peter Capaldi has "incredible hands" and a great "run”, added Coleman.